BUELACH, Switzerland - An air traffic controller on trial in Switzerland over a fatal in-air collision said Tuesday one controller was left on at night in Zurich.

Marti Luthi, the first of the eight defendants to testify in the trial, said the night-time controller staff was reduced to keep costs down, RIA Novosti reported. Luthi also denied overwork could have prevented controller Peter Nielsen from warning pilots earlier that their planes were on a collision course.

Eight Swiss air traffic controllers were on trial for negligence in the crash five years ago of a Russian Tupolev 154 airliner and a Boeing 757 cargo jet. The planes crashed over Lake Constance, at the border between Germany and Switzerland.